JPH07112119B2 - Positioning device for electronic components - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to, for example, the position of an electronic component to be automatically mounted and the position of the electronic component for which inclination information is obtained.
It concerns a deciding device .

[0002]

2. Description of the Related Art Recent electronic components reduce the number of assembling steps by performing automatic mounting and ensure the assembling accuracy. For this purpose, it is necessary to accurately mount the electronic component at the mounting position.

If a two-terminal component such as a resistor or a capacitor has a small number of terminals, it is not required to have strict accuracy in mounting. However, like QFP, a large number of leads come out from the four sides, and the leads are the same. If the distance is about 0.5 mm, strict mounting accuracy is required. For this reason, it becomes difficult to mount the device accurately by simply controlling it.

Therefore, conventionally, the mounting position is imaged by a TV camera, the position and inclination of the electronic component are obtained from the imaged result, and when the position and inclination are more than a predetermined amount, position correction is performed.

[0005]

However, in recent years I
The number of pins of C is large, and therefore the package is also large, and some of them exceed the size that can be captured by a TV camera. In such a device, the focal length of the TV camera is adjusted so that the entire IC fits on the screen. However, if such a method is adopted, there is a problem that the resolution is lowered and the accuracy is sacrificed.

[0006]

In order to solve such a problem, the present invention takes an image of a lead group at at least two opposite corners of an electronic component around which a large number of leads are regularly arranged. Then, the lead group of the non-imaging portion is estimated from the position information of the imaged lead group, and the center position and inclination of the electronic component are estimated from the imaged lead group and the estimated lead group. In order to carry out this method, an imaging device for imaging a lead group in at least two opposite corners of an electronic component in which a large number of leads are regularly arranged is provided, and an analog image from the imaging device. An A / D converter for A / D converting the signal,
First for storing image data from the A / D converter, respectively
And the second image memory, and a predetermined brightness of the image data read from the first and second image memories.
Lead tip position detecting means for detecting the lead tip position by performing grayscale processing on the image data having the above luminance, lead position information estimating means for estimating lead position information of an unimaged portion from the detected lead tip position information, and imaging And a position estimating means for estimating the position and inclination of the electronic component from the read lead information and the estimated lead information.

[0007]

The lead information of the non-imaging portion is estimated by the lead information obtained from at least two corners of the electronic component,
The entire lead information is obtained from both data, and the position and tilt information of the electronic component is obtained.

[0008]

FIG. 1 is a block diagram showing an embodiment of the present invention. In the figure, reference numeral 1 is a TV camera, which is installed on an arm of a robot or the like and is adapted to capture an image including leads at two opposite corners of an electronic component such as a large QFP. It is to be noted that the object to be imaged has a structure in which leads are arranged at equal intervals on four sides, or the leads are arranged regularly so that the information of the rest of the side can be estimated from the information of the corners. Reference numeral 2 denotes an A / D converter that converts an image signal captured by the TV camera 1 from an analog signal to a digital signal,
3 and 4 are first and second image memories for storing the respective A / D converted images, 5 is a changeover switch for switching the first and second image memories, and 6 is a position of the tip of each imaged lead in the axial direction. A lead tip position detection unit, 7 is a lead information calculation unit that estimates position information of all leads of an electronic component by estimating lead position information of an unimaged portion from detected lead tip position information, and 8 is a data input unit such as a keyboard. , 9 is a memory for storing the calculation result, and 10 is a position information calculation unit for calculating the center and tilt information of the entire electronic component from the stored information.

The operation of the apparatus thus constructed is as follows. As shown in FIG. 2, of the electronic component 11, the portions 12 and 13 indicated by the alternate long and short dash lines of two corners facing each other in the TV camera 1 are imaged. The portion shown by the dotted line in FIG. 2 is the lead portion. The imaged analog image signals of the corners 12 and 13 of the electronic component 11 are A / D converted by the A / D converter 2. In FIG. 3, reference numeral 18 indicates a digital luminance signal of a lead on a scanning line among the leads.

The image data on the leads of the two opposite corners 12 and 13 of the A / D converted electronic component 11 are stored in the first image memory 3 and the second image memory 4 after being switched by the changeover switch 5. It The stored image data is read out and calculated by the lead tip position detector 6, and first, the lead tip position information of the portion imaged by the TV camera 1 is obtained. In the lead tip position detector 6, as shown schematically in FIG. 3, an arbitrary threshold value 19 is set for the obtained digital luminance signal 18, and only data having a predetermined brightness or higher is binarized to be a binary value. Get the image data. The binarized image data 20 thus obtained is processed according to the following equation to obtain the center position coordinate X0 of the lead in the axial direction. X0 = .SIGMA.Xi Fi /.SIGMA.Fi ........ (1) where Xi is the coordinate in the scanning line direction and Fi is the brightness.

Next, as shown in FIG. 2, a change point of the luminance in the column direction is detected for each lead in the upper lead group 14 of the electronic component 11 in the image pickup screen 12, and the left lead group 15 is detected in the row direction for each lead. The tip position information (coordinates) of each lead can be obtained by detecting the change point of the luminance of. Similarly, the lead tip position information of the lower lead group 16 and the right lead group 17 can be obtained for the image pickup screen 13, and thus the lead tip position information of the four sides in the image pickup screens 12 and 13 of the electronic component 11 can be obtained. You can ask.

In the above-described embodiment, the image data having a brightness equal to or higher than the predetermined brightness of the A / D converted digital brightness signal 18 is binarized to obtain the tip position information of each lead. Depending on the distribution state of the signal 18, it is possible to improve the accuracy by obtaining the density processing (multi-value processing). The gradation process will be described with reference to FIG. If image data (data of coordinates 10 to 14) having a predetermined brightness, that is, a brightness of a threshold value 19 or more is extracted and processed according to the equation (1), the center position coordinate X0 (shading) of the lead in the axial direction. Is as follows.
Center position coordinate X0 (shading) = (10/8 + 11/11 +)
12 ・ 14 + 13 ・ 11 + 14.9) / (8 + 11 + 1)
4 + 11 + 9) = 638/53 = 12.04

On the other hand, when the center position coordinate X0 (binary) of the lead in the axial direction by the above-mentioned binary processing is obtained according to the equation (1), the following is obtained. Center position coordinate X0 (2
Value) = (10 ・ 0 + 111 ・ 1 + 12 ・ 1 + 13 ・ 1 + 1)
4.1) / (1 + 1 + 1 + 1) = 50/4 = 12.50
As is clear from these calculation results, the binary processing has a larger error than the grayscale processing.

Since this lead tip position information is information of individual leads, it is within an allowable range, but the tip position is an average position represented by a straight line as shown by the black circles in FIG. 4, for example. On the other hand, they are uneven. Therefore, in order to obtain the position and inclination of the entire electronic component 11, it is necessary to obtain the direction of lead arrangement and the average position indicated by white circles as shown in FIG.

When the lead arrangement direction is obtained by, for example, the least square method, a straight line 21 shown by a solid line in FIG. 4 is obtained. Then, the nominal lead pitch value and the nominal external dimensions of the electronic component 11 (from the tip to the tip of the lead that sandwiches the electronic component body between them), which are input in advance from the data input unit 8 (FIG. 1) to the lead information calculation unit 7. Also, from the number of leads on each side of the electronic component 11 and the data of the lead arrangement direction 21 (solid line portion) obtained by actual measurement, the average position of the leads and the average lead position for the non-measured dotted line portions are calculated. Find the line direction. At this time, if there are many measurement points, accuracy is improved by excluding information on leads (marked with Δ) that deviate from the allowable value as shown in FIG.

When this data is obtained for the four sides of the electronic component 11, the position information of all the leads can be obtained as shown in FIG. This data is stored in the memory 9, and using the stored information, the position information of the center 22 of the electronic component 11 is obtained by the position information calculation unit 10 by the following equation. X = (ΣX1n + ΣX2n) / 2 n (2) Y = (ΣY1m + ΣY2m) / 2 m (3) The tilt information of the electronic component 11 is opposite as shown in FIG. A straight line 111 connecting the tip ends X11 and X21 of the lead to X1n and X2n
It can be obtained by obtaining the average value of the inclinations .theta.1 to .theta.n of .about.11n.

In the above-mentioned embodiment, the measurement of the electronic component 11 by the two-division visual field is described.
The measurement by the four-division visual field using each corner can be similarly performed by using four image memories, and the estimation accuracy can be significantly improved as compared with the case of using the two-division visual field.

[0018]

As described above, according to the present invention, since the whole information is obtained from the information of the two corners of the electronic part which face each other, the whole electronic part cannot be imaged by the TV camera. Even if there is, it has an effect that accurate position information can be obtained. In addition, the read image data out of the read image data has a predetermined brightness or more.
Image data with the brightness of
Since the position is calculated, position detection is performed compared to the one that performs binarization processing.
It has the effect of high accuracy.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing an imaging range.

FIG. 3 is a diagram showing a luminance signal of a lead.

FIG. 4 is a diagram showing an example of position information of leads on a predetermined side.

FIG. 5 is a diagram showing another example of lead position information on a predetermined side.

FIG. 6 is a diagram showing lead position information for the entire electronic component.

[Explanation of symbols]

 1 TV camera 2 A / D converter 3 First image memory 4 Second image memory 5 Changeover switch 6 Lead tip position detection unit 7 Lead information calculation unit 8 Data input unit 9 Memory 10 Position information calculation unit 11 Electronic components 14 to 17 Lead group

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Claims (1)

[Claims] 1. A large number of leads are regularly arranged around the periphery.
In at least two opposite corners of the electronic component
An image pickup apparatus for picking up an image of the lead group and an A / D converter for A / D converting an analog image signal from the image pickup apparatus.
A D converter and a first for storing image data from the A / D converter, respectively
And the second image memory and the image data stored in the first and second image memories.
The brightness of the projected image data that exceeds a certain level
The lead image position is detected by processing the image data
Lead tip position detection means and the lead position of the unimaged portion from the detected lead tip position information.
The position information is estimated from the read position information estimating means for estimating the position information and the captured lead information.
From the position estimation means to estimate the position and inclination of the child parts
Positioning device for electronic components.